The Cancer Pharmacology Core Facility (CPCF) provides an analytical laboratory for accurate and sensitive chromatographic determination of chemotherapeutic drugs and some drug metabolites. The facility staff provides the expertise necessary for development of thoroughly validated drug determination methods. The staff also participates in the design of clinical studies of chemotherapeutic agents by specification of sample collection methodology and recommendation of sampling intervals on the basis of expected pharmacokinetic behavior of studied therapeutic agents. The facility determines drugs in dosage formulations as an element of study design in most of the clinical trials in which we participate. The CPCF has an atmospheric pressure ionization triple quadrupole mass spectrometer (API/MS) which was purchased with NIH BRS shared instrument program grant funds. This instrument is very selective and sensitive toward certain categories of small molecules which include many cancer treatment drugs of low molecular weight. This instrument enables us to bring analytical methods into operation sooner than is possible with optical chromatographic detectors. The availability of this instrument within the CPCF has enabled the Cancer Center to attract funding for clinical trials of thalidomide in combination with docetaxel, and OSI-774 in combination with docetaxel. The facility maintains a database of these analytical results, and it conducts pharmacokinetics analysis of those results.